Habrobathynella borraensis n. sp. (Syncarida: Bathynellacea: Parabathynellidae) from the Borra Caves of southeastern India, with a note on the taxonomic significance of paragnath morphology

Abstract

Up until now, the genus Habrobathynella Schminke, 1973 had ten species in the world. Of these, two are known from Madagascar and eight from India. Habrobathynella borraensis n. sp. is described herein from the Borra Caves, southeastern India. This is the first cavernicolous species of the genus. The species has a unique combination of characters: male Th VIII elongate, somewhat subquadrate in lateral views, with both dentate and inner lobes moderately produced and reaching about the level of exopod; outer lobe thumb-like, much shorter than basipod and fused with protopod; exopod distinct from basipod, claw-like, incurved in lateral views and with denticulate apical margin; female Th VIII in the form of triangular lobe lying anteriorly; uropodal sympod with inhomonomous row of 4 spines, ultimate spine longer and thicker than proximal ones; pleotelson protruded at postero-lateral angle and shorter than caudal furca; and maxilla with 1 normal seta on first segment. The affinities of the new species with its congeners, especially Habrobathynella nagarjunai Ranga Reddy, 2002, are briefly discussed. The paragnath morphology is illustrated afresh for seven of the eight Indian species, and its usefulness as a species-specific criterion discussed. The length of the outer seta vs. the apical, inner seta of the uropodal exopod is also proposed as a new specific feature. Furthermore, a brief note on the biogeography of the species of Habrobathynella is added.